A DA conversion device requiring high-speed performance includes a current output type DA converter which can be easily increased in speed. The device converts an output current from the DA converter into a voltage with a current-voltage conversion circuit formed of an operational amplifier, and then outputs the voltage thus obtained.
In the meantime, an electron beam deflection circuit in an electron beam exposure system and the like, or a control circuit in a MRI (magnetic resonance imaging) apparatus and the like may sometimes require a relatively high output voltage ranging from several tens of volts to several hundreds of volts, for example.
In a DA conversion device used for such applications, a current-voltage conversion circuit adopts an operational amplifier which is operable at a high voltage.
However, commercially available high-voltage operational amplifiers have a low operating speed and may cause restriction in operating speed of such a DA conversion device.